It's hard to name more important part buildings than the roof. It is chosen taking into account weather conditions and materials that should ensure its durability and reliability. It goes without saying that the attractive appearance of the roof also plays an important role. With all the variety of today's choices, the unusualness of hip roofs deservedly places them in one of the first places in adding attractiveness to any private home.
What it is?
The hip roof consists of two inclined surfaces that are shaped like trapezoids, plus a pair of shorter slopes that are shaped like an inclined triangle.
The main difficulties in arranging traditional hip roofs occur at the stage of erecting rafter structures, which consist of slanted, row and outer rafters.
Hip roofs have excellent resistance to wind loads and generally have high performance characteristics.
At the design stage it is necessary to comply with:
- choosing the optimal material for arranging the roof structure;
- determining the intensity of precipitation characteristic of the construction site;
- setting average and maximum wind resistance values.
Taking into account the above indicators, you can calculate the optimal value of the angle of inclination of the slopes and the heights of the roof structure.
To perform calculations and draw up a project, you can use the services of a specialist or select projects from an open source. Having the proper skills, the mentioned activities are carried out independently.
Peculiarities
The roof about which we're talking about, is designed in a unique way. A larger slope is used on any roof, but a short one makes this design worthy of attention.
Design roofing system such that the slopes do not compensate for the vertical projection of the building in length, and the remaining free area is filled with two short hips.
If you try to draw up a diagram of a hip roof structure yourself, you need to use a marking strip and Pythagorean tables.
The support for the hip roof rafters is the so-called “mauerlat” and ridge beams.
The composition of the roofing “skeleton” is as follows:
- Support base (mauerlat). It is made of timber 100x150 mm or 150x150 mm. It depends on the design features Houses. The horizontal fastening of the Mauerlat is provided by four jibs, which give rigidity to the entire structure. The Mauerlat is made of thick timber and attached to the upper end of the wall using a pin or dowel.
- Racks installed along the central axis of the floors along their long sides and reinforced with temporary supports. Subsequently, ridge beams are attached to them. Their height is chosen depending on the slope angles. Accordingly, the higher the racks, the smaller the angles between the rafter legs.
- Ridge beam- these are the upper horizontal crossbars that lie on the rack and serve as supports for the rafters. Ridge beams are attached to the post; they serve as supports for the main rafters.
- Main rafter It is supported on a mauerlat and a ridge beam and is secured to them with special galvanized steel plates.
- Diagonal, or the sloped rafter goes from the end of the ridge beams to the corner of the buildings. The temporary post fastening is removed when all diagonal rafters are installed.
- Narozhnik It is attached from below to the Mauerlat, and from above to the slanted rafters. Used as a continuation of the plane of the main slope. They have intermediate distances, just like between the rafters.
- Sprengel. It goes from the Mauerlat jib to the diagonal rafters and provides reinforcement to the roof.
- Strut. Needed to enhance the roof's resistance to wind. Theoretically, it is installed on the windward side (from the “wind rose”). In practice, the brace can be used from any side.
- Lathing. They are carried out inside along the rafter leg and determine the base of the roofing “pie”. Rafter system designs include some important elements with strictly defined functions for each.
Advantages and disadvantages
Advantages:
- Compared to a gable roof, a hip roof has minimal resistance to wind. Because of all the inclined slopes, the wind does not put pressure on the pediment.
- The structure has greater rigidity due to the presence of an angular rib that connects to the support beams of the skates.
- There are protruding overhangs that further protect the walls.
- Great aesthetic appeal.
Flaws:
- complex calculations and installation;
- high cost;
- small attic space;
- lack of attic;
- sunlight enters only through special windows.
Kinds
When considering the types of hip roofs, it is necessary to take into account their varieties, the choice of which affects the design of the rafter systems.
- Classic type. The diagonal ribs rest on the ridge support beams, the overhangs are located at the same height. The pediment is triangular, the slope is trapezoidal.
- Tent type. The ridge support beam is missing. The diagonal rib ends at one point, and an ordinary short rafter is adjacent to the ribs. This is how roofs are built if the building in vertical projection is a square.
- Half hip type. The gables are vertical; window openings are installed in them. There are two varieties of the half-hip type - Dutch and Danish.
- Broken hip type(attic hipped). It represents the greatest difficulty during construction, since the slopes are of different sizes and have different angles of inclination. This type makes it possible to rationally organize the internal roof space and allows you to give the roof an unusual appearance.
There are also several other types of roofs - one-story, two-story, cuckoo, bay window, L-shaped.
How to choose?
Question of type selection hip roof depends only on the preferences of the owner, or more precisely, on the thickness of his wallet. For example, gable windows will cost no less than regular ones, and metal tiles on the veranda roof will be more expensive than other materials.
Calculation
The rafter system is calculated taking into account the following prerequisites:
- Wind loads. The stronger the wind, the more positioned the slopes are, which, in turn, strengthens the entire structure.
- Precipitation. The more that falls, the steeper the slopes become, avoiding the extra weight of snow/rain that collects on the roof and puts pressure on the rafters.
- Type of materials from which the roof is made. This must be taken into account at the project stage.
- Roof insulation. Here the distance between the rafters will depend on the width of the strip of materials with which the insulation will be produced.
The slopes of the angles of the slopes determine the laying of the rafters. Accordingly, the laying of intermediate rafters is calculated as follows:
- the top trim of the end wall is marked with the center line;
- then calculate the half-thickness of the ridge beam and draw a line to define the first central intermediate rafter;
- then the end of the batten is aligned with the line of the marked center of the intermediate rafter;
- mark the other end of the rail with the inner line of the side wall;
- get a point, which will be the laying of the intermediate rafters.
The proportion of the length of the rafter and its laying is calculated using a coefficient that depends on the angles of the slopes. The lengths of the rafter legs are determined by multiplying the laying by the coefficient.
Installation stages and subtleties
When purchasing roofing material, you need to know its total footage. Usually, to do this, its total area is conditionally divided into parts in the form of simple geometric shapes and calculations are made for each.
In this way, the financial costs for roofing material and construction are determined in advance, and the need for arrangement and the exact configuration of the sheathing are determined.
As a result, a diagram of the rafters will appear.
It is possible to develop a preliminary diagram with your own hands, but it is preferable to trust the drawings to a specialist. It must be borne in mind that the complex configuration of the roof requires accurate calculations of rafters and material. All these details will greatly affect the price and installation time.
The drawings must include indications of the purpose of the materials, their installation locations and fastening methods. The most important fragments of the rafters should be included in separate drawings and described in detail.
The production of a drawing diagram can become a support for the manufacture of blanks and subsequent installation.
Preparation
Preparation of rafters is the most difficult and time-consuming stage, because there are:
- the need to ensure a given rafter angle;
- different lengths of the narozhnik (short rafter);
- the presence of a diagonal rafter (sloping), which is given special treatment.
The slanted rafter carries more significant loads than the main one, for this reason it requires manufacturing from a higher quality material. Also, the lengths of the diagonal rafters exceed the standard ones.
To avoid buying different lumber, splicing (pairing) of edged boards is used to obtain a given length.
Splicing technology has the following advantages:
- continuous beams of a given length are obtained;
- increase the strength of diagonal rafters due to large (double) sections;
- the calculation and purchase of materials is simplified (length and cross-section dimensions are unified);
- it becomes possible to use boards that are designed to form ordinary rafters
Mauerlat is called wooden beams with a large cross-section (100x100 and 100x150 mm), which are mounted along the perimeter of the house. The highest quality wood is used for it.
The peculiarities of the installation of the Mauerlat are that the timber is connected along the length with an overlap, and not end-to-end, and it is attached to the wall using many connecting areas with the base of the walls. The joints are reinforced with metal staples.
The Mauerlat serves as the base of the rafter leg and needs protection from getting wet. Therefore, the wall is separated from the timber by a hydraulic barrier (you can use roofing felt/roof felt, etc.).
If the house is brick, (aerated concrete, foam concrete, wood concrete), the mauerlats are laid on a pre-poured reinforced concrete layer, into which mounting studs are pre-installed. They have a diameter of 10 mm and above and should extend beyond the level of the Mauerlat by 25-35 mm in increments of 1100-1300 mm.
A purlin is a beam that is installed parallel to the Mauerlat. It works as a base when installing additional support under rafter leg. The arrangement of purlins is an optional stage of work, and is performed when constructing a hip roof of large footage or with a complex configuration.
It is necessary to mount the ridge only with precise measurements. The roof rests on the ridge beam, so it is necessary to install it correctly and check its height.
At the stage of installing the rafter leg, there is a difference of opinion regarding the sequence of operations. Therefore, it is possible to distinguish two directions:
- Mount the central rafter, and then the diagonal one. This is a simpler sequence.
- Mount the diagonal rafter, then the rest.
The bottom of the rafter legs stands on the mauerlat. To make the connection rigid, it makes sense to strengthen the connecting nodes with metal elements(bracket, plate, corner).
The diagonal rafter experiences significant load, so it is reinforced using means such as:
- Installation of racks. Mounted on floors perpendicularly.
- Installation of struts. Mounted at angles. Angles are not critical. It is important that the brace strengthens the diagonal rafters.
- Sprengels are short T-shaped beams rotated 180 degrees. They are used for significant span lengths and are installed so that the bases of the trusses are oriented across the diagonal rafters.
The ordinary rafter is installed in the same way as the central one, which forms the edge of the trapezoid. The lower parts rest on and are attached to the mauerlat, and the upper parts rest against the ridge beams.
Narozhnik is made strictly from a whole piece of material. Where it adjoins the long rafters, mark a notch or install a support beam. The junction area is reinforced with metal elements.
The roof frame is installed only after the roof frame has been formed. This is the last element of installation of the rafter device.
Tools
The design of the roof and the arrangement of connections determine a set of tools that must be prepared before starting work.
- When working with wood, you will need levels, hacksaws, hammers, tape measures, marking cords, and staplers.
- When working with metal, you will need electric drills, riveters, and metal scissors.
Tools and consumables must be prepared before starting work, because... complex installations rafter systems involve a lot of work on cutting various materials.
To simplify measurements and be able to unify the size of parts, it is recommended to replace the tape measure with a measuring rod. It is most often proposed to make such a plywood structure with a width of 50 mm.
Carrying out work
The work is carried out stage by stage and there is no place for haste. Each step must be carefully considered as hip roof designs are complex. In this context, it is also hardly possible to provide step-by-step instructions, since the views of the craftsmen on certain aspects of installation are too different. Only general recommendations are available.
A hip roof is a roof that maximally satisfies the requirements of aesthetics and originality and fits harmoniously into almost any surrounding landscape. Moreover, its rafter system is still the most reliable geometric design for protecting a house from wind loads.
The main task of the roof is to protect the house from precipitation. In order for the roof to be as functional as possible, it is designed with a slope to remove the bulk of snow and rainwater. At the same time, the entire supporting structure of the rafters must be strong in order to withstand significant loads.
The best way to do this type of work would be a classic gable roof, or a hip roof rafter system: the construction scheme of such a structure makes it possible to obtain a roof that is distinguished by:
- high reliability,
- versatility,
- long service life,
- the streamlined shape eliminates the effect of windage, that is, wind load in the gable area.
Types of hip rafter frames
This version of the rafter system, unlike the classic gable one, is an “envelope”. In addition to the two main planes of the slopes, instead of the gables, two additional ones are assembled in the form of a triangle; these are the so-called hips. Depending on their purpose, they can be attic or non-attic.
It’s worth mentioning right away that this type of roof is not suitable for arranging a residential attic floor, because the four planes of the slopes limit the internal space. However, if desired, you can use such types of designs as Danish or Dutch.
An example of a Danish roof with truncated hips
Half-hipped Dutch-type roof with a residential attic
A hip roof is an excellent solution for buildings with original architecture, having elevations, projections, various turrets, and an attic floor.
Both options include a roof space that can be used as additional living space. The slopes of the roof planes do not significantly reduce the usable area due to the trimmed hips.
- The classic type of such a roof provides for full four slopes with diagonal rafters connecting the corners of the building with the top of the entire structure, which is crowned with a ridge of the required length. The following elements are used:
- Hanging rafters with all the details: beams, purlins, ties.
- Diagonal.
- Sloping, forming the contours of planes.
- Another option, a hip hip roof, is a rafter pattern in which the diagonal elements converge at one point, forming a pyramid or tetrahedral tent. The assembly of such a structure involves the use of layered and hanging principles for installing frame parts.
Perfect option roofing material For hip roof it will be soft bitumen shingles, since large sheets of metal tiles or corrugated sheets will have to be cut, after which a lot of waste will remain.
All types of hip and half-hip roofs are designed with plane inclination angles from 10-12 degrees to 60. It is most optimal to use the accepted conventional bevels at an angle of 25-30 degrees.
Hip roof rafter system: device diagram
Construction work load-bearing frame roofs are carried out in the following sequence:
- Mount the Mauerlat.
- Place the bench in the places where the racks will be located.
- Install the racks on the floor, strictly vertically, for the ridge girder. If necessary, the racks are secured with struts.
- To attach the ridge fitting, use a level and plumb line. The quality of the design depends entirely on the accuracy of the installation.
- The bevels are mounted: the lower end is to the Mauerlat, and the upper end is to the ridge girder.
- Intermediate installations are also installed using the same technology.
- The spigots are being installed.
The device offers the following bearing structures:
- diagonal;
- intermediate;
- sprigs (corner).
Installation of diagonal parts
Four diagonal (sloping) boards are directed towards external corners and converge on the ridge run. Their lower supports may differ - it depends on the material with which the house is built:
- wooden chopped or cobblestones - the upper crowns of the log house;
- frame - top trim;
- brick (stone) – Mauerlat, through which the concentrated load from a wooden structure is distributed onto the masonry walls.
- wooden beam With square section(100 x 100mm). It is laid either in the center of the wall, or closer to the inner edge and secured to the wall using wire rod twists (this way you can protect the structure from strong gusts of wind). One end of the twist is screwed to a crutch, which is driven into the joint of the masonry (300 mm from the top of the wall), the other is attached to the beam.
- To maintain free access to inspect the rafters and rafters, a distance of at least 400 mm is left from the bottom of the Mauerlat to the top of the attic floor.
- All places where wooden elements come into contact with brickwork isolated with a layer of waterproofing.
- The top of the mowing boards rests on a ridge beam, which is a wooden beam with the same cross-section. Under the ridge beam, due to the absence of brick gables in the design of this type of roof, wooden posts (section 100 x 100 mm) are installed at intervals of 3-4 m, which rest with their lower end on the bed.
It can be laid:
- if there is an internal load-bearing wall, a board with a section of 50 x 150 mm is placed on it;
- through the brick columns onto the floor slab - a beam with a square section of 150 by 150 mm.
In any case, roll insulation must be laid under the bed.
- Diagonal rafters are longer than usual rafters, in addition, the ribs rest on them, so the load on them is one and a half times greater than that of ordinary ones. For this reason, mowing boards are made paired - they consist of two sections of ordinary ordinary boards.
- Supports (one or two) are installed under it in the form of racks made of timber or struts (the cross-section of both is 100 by 100 mm). Thus, the estimated length of the mowing leg is reduced. The struts rest against the bed at an angle of 45°.
Features and types of supports
Most often, when building houses, they use the usual hip roof scheme, less often Dutch or Danish.
The support system for roof assembly can be used in two types:
- Hanging rafter frame diagram. Typically used in the construction of small residential buildings, in which the design does not provide for internal load-bearing walls. In this embodiment, the main vertical supports are installed on the ceiling beam in one row.
- Layered. In the presence of load-bearing walls inside the house you can install two or three rows of vertical supports. This simplifies the assembly of the hip roof, due to the presence of a larger number of attachment points, and also makes it possible to design.
note
When assembling, it is better to give preference to the latter option, which will make it possible to evenly distribute the weight by resting the rafters on several supports over the entire area.
Stops for diagonals are used in three types:
- Rack. Usually a beam of suitable cross-section, installed with a stop according to one of the options. Between it and the ceiling (the ceiling itself), there must be waterproofing.
- Strut. It consists of two beams, their ends resting on the frame post, and the other two are supported by the converging diagonal rafters of the slope. Their angle can vary from 45 to 53 degrees.
- Sprengel. This is a beam that is laid on two walls that meet at an angle. A vertical stand is installed on it, supporting the sloped rafter in the lower part. Another option for a hip stop consists of two parts of a truss truss laid at the corners of the building. And also the truss itself - a vertical post supporting the diagonal, with an emphasis on the truss. With a small angle of the structure, the snow load increases, so it becomes necessary to strengthen the wooden structure with a truss. If it is necessary to strengthen the upper part, a truss truss is used. In this case, the truss (vertical post) is strengthened with the help of two struts.
Trunnion installation
Also, depending on the frame design, it can be used different system supports of diagonal sloping beams to the ridge girder.
- If the roof structure has only one purlin that acts as a ridge, then the support is provided directly on its console.
- With the option of two purlins, and using boards as rafter legs, diagonal sloping beams rest on both purlins.
- In the case of two runs and using beams as slings. legs, emphasis is placed on both runs. In the ridge area, the diagonal sloping parts have a short piece (break) as a support, which stitches the adjacent rafters together.
Scheme of support for slanted rafters with emphasis on the short one
With this fastening, the heel of the rafter element is cut to the required angle, nails are used as fasteners, and, if necessary, additional clamps are used to strengthen the connection.
The opposite end of the diagonal is fixed with emphasis on the mauerlat, or the corner beam installed before it. In this area, staples or nails driven through the lining from a wooden lath are used as fastening.
Installation of frames and intermediate rafters
Narozhniki (corner elements) are called rafter half-legs because of their shortened length. At one end they rest on the diagonal leg, and at the other on the base beam. To ensure that the load on the corner bevels is distributed evenly, they are attached in different places.
- The lower end rests on the mauerlat, and the upper end rests on the ridge beam. Install in increments of 1.0-1.2 meters. Sections are calculated based on the beam design (one- or two-span), pitch and weight load snow cover and the frame itself. The snow load is calculated taking into account the angle of inclination.
- The free length of intermediate boards in the frame is limited. When flying over a building:
- 8 - 10 m - one support (strut or stand) is installed under each leg;
- 10 - 12 m - two supports.
- Every second leg is attached to the wall using twists (double wire, diameter 4 mm), which, using crutches, are driven into the brickwork seam below 300 mm from the edge of the wall.
- The intermediate rafters and the mauerlat are connected using a back bracket.
Fasteners for spigots
Narozhniks are installed as rafters on the diagonals of a sloping roof. With their help, the hips themselves and the triangular sections of the main planes of the roof are formed.
Installation of external parts is carried out in two main ways:
- By cutting. On the diagonal, a sample of material is made, forming a nest for the heel of the sprig. The location between them should be at least 200 mm, while the cutting is made on both sides so that it does not coincide.
- With pre-installation of cranial bars. In the lower part, on both sides of the diagonal rafter, a beam with a cross-section of 50×50 mm is packed along the entire length of the slope beam. In this case, the narozhniki cut under the cranial block, and rest one against the other. This scheme is more preferable, since the structure is much more rigid due to the additional support.
However, before you start purchasing materials, as well as assembling according to the chosen scheme, you need to make all the calculations of the parameters of the hip roof.
Hip roofs give the building an elegant and complete appearance; its slopes withstand gusts of wind and snow loads well. Under this type of roof you can place a large attic space. We will talk about the features of the rafter group of hip roofs, about the methods of calculation and installation of rafters, as well as about the roofing pie, ventilation and insulation of the structure. Let us dwell on the description of the properties of roofing materials and tell you how to make a hip roof for a gazebo with your own hands.
Design features of hip roofs
Hip roofs give the building a certain chic, but the peculiarity of their design is that they perfectly withstand multidirectional wind influences. This is due to the rigid rafter system and the presence of triangular and trapezoidal slopes. Increasing the height of the ridge and the slope of the slopes makes it possible to place a habitable room under the hip roof.
The hip roof consists of two triangular and two trapezoidal slopes, which rest on a ridge girder
The following distinctive features can be considered as design features of hip roofs:
The unique rafter system determines the strength characteristics of hip roofs and their resistance to weather conditions.
Preparing a roof project
When preparing a hip roof project, it is necessary to determine the height of the ridge, since the angle of inclination and length of the slopes will depend on this parameter. For a habitable attic space, the ceiling height must be at least 2.3 meters in accordance with fire safety standards.
The angle of inclination of the slopes is associated with the choice of ridge height, since this parameter determines the volume of the comfortable living area
To prepare the project, after choosing the height of the ridge, it is necessary to take measurements that will help calculate the length of the rafters, the area of the slopes and the volume of the habitable room. To design a roof you will need the following parameters:
The developer determines whether the attic space will be cold or habitable, because the method of fastening the ridge girder, the presence or absence of pitched windows, the design and number of rafter elements. After preparing the project, you can begin to calculate the hip roof and elements of the rafter system.
According to the author of this article, to design a hip roof, especially one complicated by bay windows, gables and hipped fragments, it is better to use the services of a design engineer. When building the attic roof of a country house, the author was greatly helped by a set of drawings with the calculated length of the rafter beams, the method of connecting them, the angles of the cuts and the number of fasteners. The list of insulation and roofing materials indicating the area and installation order made it possible to order them in advance. Procuring project-based components minimizes material waste and saves time. The calculated dimensions of the rafter system and a clearly defined assembly sequence eliminated defects, unnecessary calculations and additional adjustments. Installation work was carried out by a team of four people with little construction experience, which managed even the difficult section of joining the slope with the roof of the bay window, however, with the help of consultation from the author of the project.
At independent design you need to start by calculating the basic parameters of the roof and the dimensions of the rafter group, creating your own drawings and layout layouts.
Hip roof calculation
When calculating the parameters of a hip roof, the house owner sets the height of the ridge for practical reasons. For a cold attic, it can be less than two meters, and when building an attic roof, you need to remember that according to SNiP, the height of the ceilings of a living space must be at least 2.3 m.
During preliminary calculations, the height of the ridge is first determined, and then the length of the central purlin, the size of the main and diagonal rafters
The length of the central purlin at equal angles of inclination of the slopes is selected so that the ends of the purlin are located at the same distance from the side and end walls. In the course of further calculations, the dimensions of the rafters, extensions and auxiliary elements are determined. It is necessary to choose the type of rafter system, because if for hip roofs with an uninhabited attic layered rafters are more typical, then for roofs with an attic both layered and hanging types of rafter connections can be used.
Calculation of slope angle and rafter length
The roof's resistance to wind influences and its ability to withstand snow loads depend on the angle of inclination of the slopes. The slope of the slopes is the most important parameter for calculating the length of the main and diagonal rafters, as well as rafters. We will take the following parameters as the basis for the calculations:
- ridge height H k = 3 m;
- building length L ds = 10 m;
- building width L dts = 6 m. We denote half of this size as L pts: L pts = 3 m;
- ridge length L k = 4 m;
- distance from the house wall to the ridge girder T = 3 m.
Calculations are carried out in several stages.
Table: values of trigonometric functions for the slope angles of the attic roof slopes
| a, deg. | tg a | sin a |
| 20 | 0,36 | 0,34 |
| 25 | 0,47 | 0,42 |
| 30 | 0,58 | 0,5 |
| 35 | 0,7 | 0,57 |
| 40 | 0,84 | 0,64 |
| 45 | 1 | 0,71 |
| 50 | 1,19 | 0,77 |
| 55 | 1,43 | 0,82 |
| 60 | 1,73 | 0,87 |
Calculation of the area of hip roof slopes
The area of the slopes must be known to calculate the quantity building materials and drawing up a cutting diagram. The hip roof has two triangular and two trapezoidal slopes; to calculate their area we will use standard formulas from school course geometry.
To calculate the area, it is necessary to increase the height of each slope by the size of the eaves overhang and keep in mind that their lengths will also increase.
Calculation of the volume of the attic space
Calculating the volume of habitable under-roof space will be needed when calculating the heating and air conditioning systems of the attic. Since under the hip roof there is a multifaceted living space with varying height and shape, to calculate the volume it needs to be divided into simpler shapes. Usually we consider the section of the attic formed by some rafter, divide it into rectangles, triangles and trapezoids, calculate their areas using the above formulas and multiply by the length of the attic. The volumes of each part obtained in this way are added up and the total volume of the attic is obtained.
To calculate volume attic room it is divided into elementary figures, the volume of which is calculated separately and added to each other
If, when dividing the attic, more complex elements are separated, then their volume is calculated using the formula V = S H, where S is the cross-sectional area, H is the length of the element.
Video: calculation of the hip roof rafter system
Roof layout layout
The model is a reduced copy of the roof, from which you can determine optimal height ridge and the angle of inclination of the slopes in relation to the size of the building. The diagram of the rafter system of a hip roof, made in the form of a drawing indicating the dimensions and location of the elements of the rafter group, is called a layout layout. Such diagrams indicate the location, length and height of the ridge girder, as well as the size and number of main, diagonal and outer rafters.
The diagram of the rafter system indicates the dimensions of the elements, their installation location, installation method and angles of inclination of the rafter legs.
The drawing indicates the method of fastening the parts, the angles and dimensions of the insert, the pitch of the rafters and the arrangement of the eaves overhang. Using the diagram, you can calculate the amount of materials, cut and place individual parts at the installation site.
It is necessary to take into account that the calculated data requires practical verification, therefore, before making templates for cutting parts, it is necessary to carry out a trial joining of the main and diagonal rafters.
Hip roof rafter system
The hip roof is formed by four slopes, and its rafter system contains elements of a gable and hip roof. Basically, layered rafters are used, which rest on a ridge girder fixed to racks. The hip roof consists of the following elements:
- a mauerlat is mounted along the perimeter of the walls; if there is an internal main wall, a bench is attached to it;
- tie rods or floor beams are installed on the Mauerlat;
- a ridge girder is attached to the vertical posts;
- the main rafters rest on the mauerlat and ridge girder, forming trapezoidal slopes;
- diagonal rafters form triangular slopes;
- sprigs are shortened rafters that form a load-bearing frame between the diagonal and row rafters;
- struts and trusses are used as additional supporting elements;
- fillies are used to lengthen rafters and beams;
- the counter-lattice creates ventilation gap;
- sheathing is used to secure the roof covering.
The hip roof consists of standard elements and specific rafter units that provide the necessary structural strength
In addition, the rafter legs are reinforced with crossbars and additional racks. Often these elements form the walls and ceiling of the attic space.
Mauerlat and its dimensions
The Mauerlat is the connecting link between the building frame and the rafters and represents solid timber, attached to the wall with threaded rods. To eliminate the bursting effect of the rafters on the walls, the Mauerlat bars must be attached to a continuous reinforced belt. The studs in increments of 80 to 100 cm are embedded in a monolithic belt.
The Mauerlat runs along the upper perimeter of the building and is attached to the reinforced concrete belt with studs
The Mauerlat evenly distributes the load from the roof to the walls of the building; its length is equal to the perimeter of the house. For its manufacture, pine lumber with a cross-section of 150X150, 150X200 or 200X200 mm is used. At the corners of the house, the timber is connected to each other using threaded rods.
Installation of a ridge girder
The ridge girder serves as a support for the main and diagonal rafters and is installed on vertical posts that rest on floor beams or beams. To add rigidity to the rectangular structure, it is recommended to install diagonal struts between the posts and the purlin. To install the central girder, timber 100X100 mm or 50X150 mm is used.
Installation of the central girder is carried out using vertical posts resting on the floor or on the floor beams
Most often, layered rafters are used, but for habitable attic spaces, a hanging type of rafters can also be designed to free the living space from the clutter of auxiliary structures.
The option with hanging rafters frees up the living space as much as possible from bulky structures
In this case, the main and diagonal rafters are attached to the central girder, which are reinforced with crossbars and racks that form the walls and ceiling of the attic.
The procedure for carrying out installation work
Before installing the hip roof rafter system, workplaces must be equipped with ladders, scaffolding and ladders, since ease of use significantly speeds up installation. Then they begin to assemble the roof elements in the sequence described below.
- To monolithic reinforced belt lay out the waterproofing material and place pre-drilled Mauerlat beams on it, securing them with threaded rods, washers and bolts.
The Mauerlat beams are laid on a layer of roofing felt waterproofing and secured with studs through pre-drilled holes
- Floor beams or tie beams are attached to the Mauerlat in increments of 60 to 120 cm, and vertical posts for the central girder are installed on them.
- A ridge girder is attached to the vertical posts, then the entire structure is reinforced with diagonal struts. Relative to the outer legs, the purlin should have extensions of 15 cm for attaching diagonal rafters.
The arrangement of the roof begins with the installation of the central purlin and the main rafters
- Between the floor beams and the ridge girder, rafter legs are placed in pairs, the tie-in is marked and the rafters are cut. The outer main trusses are installed, cords are pulled between them and the remaining rafter legs are placed along them.
- At long length rafters are reinforced with crossbars, struts and racks. After this, the diagonal rafters are marked.
To install diagonal rafters, it is necessary to carefully mark, cut and cut for joining with the ridge and mauerlat
- The marked diagonal rafters are cut and installed; if necessary, they are reinforced with trusses and struts.
- The eaves are marked and installed, the ends of the rafters on the eaves overhang are cut vertically, and the front boards are attached to them.
- A waterproofing membrane with an overlap of 10 cm is attached to the rafters and sills, and a counter-lattice and sheathing are installed.
Based on personal experience, the author of this article would like to recommend equipping a place at the construction site for marking, cutting and templating elements of the rafter system. It is convenient when precise goniometer tools are in one place, suitable for marking and sawing. Equipped workplace saves time when preparing parts, which are then lifted and mounted without additional adjustment. Below it is easier to prepare an assembly kit of fasteners for each stage of work.
Video: hip roof rafter system
The roofing pie of a hip roof consists of the following elements:
- rafter legs;
- vapor barrier membrane;
- insulation located between the rafters;
- waterproofing membrane;
- sheathing and counter-lattice;
- roofing material.
The roofing pie of a hip roof is used to create a certain sequence of protective layers, on which the finishing coating is laid on top
For a cold attic, the roofing pie consists of rafters, a waterproofing membrane, counter-lattens, sheathing and roofing material. Thermal insulation layer and vapor barrier film are not used here.
Ventilation of the under-roof space of an insulated hip roof occurs through a ventilated gap between the insulation and the waterproofing membrane. A ventilation gap is formed when installing the membrane on rafters with a sag of 1.5–2 cm, so air penetrates the insulation through the perforated finishing of the cornice and exits through the holes of the ridge aerators.
The roof is ventilated through eaves soffits and ridge aerators.
A vapor barrier film protects the insulation from evaporation from residential premises, and a waterproofing membrane protects the insulation layer from moisture from condensation. Condensation accumulating on the waterproofing is removed through a ventilation gap 5 cm high, which ensures air circulation and keeps the rafter system intact. In this case, the layer heat-insulating material does not lose its properties from excess moisture.
The cold attic is ventilated through perforated openings in the eaves overhang trim and dormer windows, as well as ridge aerators. Temperature difference between external environment and the attic is reduced to a minimum, so icing of the roof does not occur.
The advantage of a cold attic is that there is no difference in temperature between the roofing and the attic, which prevents icing of the roof.
With this hip roof ventilation scheme, it is necessary to remember to carefully insulate the ceiling and the upper part of the walls between the living space and the cold attic.
Video: hip roof dormer windows - cold attic
Insulation of a hip roof
Roof insulation is carried out after installation of the roof from the inside of the attic or from the outside during installation roofing pie. This sequence of work protects the insulation from unexpected precipitation. Thermal insulation material placed between the rafters in a layer of 20–25 cm.
Insulation from the inside occurs by stuffing insulation between the rafters and fixing it with a cord or fishing line
The following materials can be used to insulate a hip roof:
- expanded polystyrene with a size of 600X1200 mm and a thickness of 20 to 100 mm;
- fibrous slabs and mineral wool mats measuring 600X3000 mm and thickness from 50 to 200 mm;
- foam insulation, which includes ecowool and expanded polystyrene.
The elasticity of the mats and slabs allows them to be stuffed between the rafters in several layers with shifting the joints to get rid of cold bridges, and foam insulation is applied by spraying using special equipment.
For different types of roofing, certain types of additional elements are produced. The hip roof uses ridge strips with aerators, caps for hip joints and tees for diagonal rafters. They cover ridge and pitch joints, as well as eaves overhangs.
At the final stage of installation of a hip roof, numerous additional elements are used
Of the remaining additional elements on hip roofs, ladders, ladders, snow retainers, seals and drips can be used.
Ridge extensions
Ridge extensions have different configurations and sizes, for example, straight strip 150X150X2000 mm or semicircular R110X2000 mm. Ridge strips can have aerators different types. Let's consider the features of installation and joining of ridge extensions.
Installation of straight ridges on a hip roof is carried out with an overlap of at least 5 cm and begins on the side opposite to the prevailing winds. The planks are attached in increments of 15 to 30 cm, and plugs are mounted on the outer planks. The design of some ridge strips includes polymer aerators that provide ventilation of the under-roof space.
The joining of horizontal skates occurs with an overlap of at least 5 cm
The spinal strips are attached, starting from the cap, from the bottom up, and at the junction of the hip ridges and the ridge they are joined to the tee Y-straps. If necessary, the joints are additionally sealed.
The design of the round ridge includes stiffening ribs that serve as locks for joining individual planks. Such ribs prevent water from penetrating into the ridge space. The round ridge is attached to top bar sheathing through an aero-element, which ensures air circulation through the ventilation gap.
The round ridge is installed through a seal using special plugs
When installing any type of ridge strips, it is important to ensure that the vents are not blocked and that air circulation is maintained between the eaves and the ridge.
Wind bars and drip edges
Drips are installed on the eaves of a hip roof to drain condensate, and to protect the under-roof space from wind and rain, wind or eaves strips are mounted on the sheathing.
The drip tray on the eaves (item 7) is used to drain condensate, and the wind strip (item 5) protects the under-roof space from wind and rain
This type of extensions is installed with an overlap of at least 5 cm, the standard length of the planks is 2 m.
Video: installation of metal tiles and additional elements
Types of roofing for hip roofs and their installation
For hip roofs are used different types roofing materials, which are offered in large quantities by manufacturers. When choosing, you need to evaluate the color scheme, ease of installation, weight and durability of the roofing. The cost and effective area of the material are of considerable importance. Let's look at the most popular types of roofing:
- ceramic and cement-sand tiles;
- metal tiles and roofing corrugated sheets;
- slate and ondulin;
- soft tiles.
According to the author of the article, attention should be paid to the noise-absorbing properties of the roofing material. From this point of view, metal profiles are inferior to ondulin and soft tiles with their excellent sound insulation. In addition, condensation forms on the metal surface due to temperature changes, so measures must be taken to remove it. Soft tiles are easy to install, but they require a continuous sheathing of 12 mm thick plywood and lining material, which makes their use somewhat more expensive. For these reasons, as well as due to the light weight and ease of installation, the author of the article for covering residential country house Ondulin was chosen. During the operation of the roof it became clear that during heavy rain a slight noise is heard in the attic, and after insulating the attic extraneous sounds practically gone.
The roof covering is installed on the sheathing. Before roofing works you need to mount droppers, wind boards and brackets drainage system. Sheet materials are fastened with self-tapping screws with a washer and a rubber gasket in a checkerboard pattern. Laying the sheet covering of the hip roof begins from the center of the slope to the edges.
Installation of the roofing sheet begins with the first solid element, then the sheets are attached symmetrically to the left and right
Installation is carried out using a cord stretched along the eaves. Soft tiles are laid from bottom to top with an overlap recommended by the manufacturer.
Metal profile
Metal profiles include roofing corrugated sheets and metal tile coverings. The total width of the metal tile sheet is 1180 mm, the effective width is 1080 mm, the length can vary from 765 to 8000 mm, the lathing pitch is 350 mm. The roofing corrugated sheeting has an installation width of 1000 mm and a length of up to 6 m. The service life of these coverings reaches 50 years, while the material is lightweight and easy to install.
Corrugated sheeting is easy to install and lasts up to 50 years
Slate
Slate is heavy and fragile, so modern construction its lightweight (sheet weight 6 kg) analogue is used - ondulin.
Slate is heavy and fragile, but is still popular
The length of the ondulin sheet is 2 m, width - 0.95 m, useful area - 1.6 m 2. Ondulin is mounted on the sheathing in increments of 45 cm, with a longitudinal overlap of 20 cm, and the lateral overlap is one wave. Additional advantages: service life up to 50 years, good noise absorption, ease of installation.
The service life of ondulin reaches 50 years, while the roof is noise-absorbing and easy to install
Length soft tiles is 1 m, the average width is 333 mm, the overlap depends on the type and shape, and the thickness is 6 mm. This is a lightweight sound-absorbing material that is easy to install, lasts up to 35 years, is inexpensive, but requires a continuous sheathing and a lining layer.
Soft tiles give the roof modern look and is simply mounted on a continuous sheathing
Do-it-yourself hip roof for a gazebo
A gazebo with a hip roof creates a unified architectural space on the building site. For construction, it is necessary to build a frame like a Mauerlat and then perform the following steps.
All wooden parts of the gazebo must be treated with antiseptic and fire retardant compounds and given the appropriate color shade.
We talked about the design and calculations of hip roofs, the rafter system and the step-by-step procedure for installing its elements. We touched on ventilation, insulation and the structure of the roofing pie. Self-installation a hip roof will allow you to save money and be completely convinced of the quality of the work performed. We hope that the materials in this article will help you in building a roof for a cozy home.
Roofs hip design are becoming increasingly popular among private home owners. This is not surprising, since such a scheme is distinguished by a number of undeniable operational advantages, and in addition, it looks very original, giving the house a special aesthetics.
Some do-it-yourself homeowners may be put off by the fact that the hip roof truss system looks overly complex. Yes, it is certainly not as simple as a regular gable gable roof. Nevertheless, this rafter system is completely subject to the laws of geometry, and it is quite possible to make a preliminary calculation. Installation, of course, will require some experience in carpentry, but with good helpers, and even better – with a qualified consultant, you can take on this large-scale event.
What are the advantages of a hip roof?
We have already talked about the hip roof on the website. There the roof structure was described with the rafters resting on the mauerlat. After publishing the article, I received many requests to show how to make a hip roof with rafters supported on floor beams, and also to answer the question whether it is possible to make a hip roof with different slope angles.
Thus, I wanted to “kill two birds with one stone” with one example. Now we will look at the design of a hip roof with the rafters supported on the floor beams and with different slope angles.
So, let's say we have a house box of 8.4x10.8 meters.
STEP 1: Install the Mauerlat (see Fig. 1):
Picture 1
STEP 2: We install long floor beams with a section of 100x200 cm in increments of 0.6 meters (see Fig. 2). I won't dwell on it any further.
Figure 2
The very first to install are the beams that run strictly in the middle of the house. We will be guided by them when installing the ridge beam. Then we put the rest with a certain step. For example, we have a step of 0.6 meters, but we see that there are 0.9 meters left to the wall, and another beam could fit, but it doesn’t. We leave this span specifically for “removals”. Its width should not be less than 80-100 cm.
STEP 3: We install the stem. Their pitch is determined when calculating the rafters, about which a little later (see Fig. 3):
Figure 3
For now we are installing only the stems corresponding to the length of the ridge, which will be equal to 5 meters. Our ridge length is greater than the difference between the length and width of the house, which is 2.4 meters. What does this lead to? This leads to the fact that the corner rafter will not be located at an angle of 45° in plan (in the top view), and the angle of inclination of the slopes and hips will be different. The slopes will have a gentler slope.
It is enough to secure the stem on the Mauerlat with nails. We attach them to a long floor beam, for example, like this (Fig. 4):
Figure 4
There is no need to make any cuts in this node. Any cut will weaken the floor beam. Here we use two LK type metal rafter fastenings on the sides and one big nail(250 mm), driven through the beam into the end of the stem. We hammer in the nail very last, when the stem is already fastened to the Mauerlat.
STEP 4: Install the ridge beam (see Fig. 5):
Figure 5
All elements of this structure except the struts are made of 100x150 mm timber. Struts made of boards 50x150 mm. The angle between them and the ceiling is at least 45°. We see that under the outer posts there are beams resting directly on five floor beams. We do this to distribute the load. Also, to reduce the load on the floor beams and transfer part of it to load-bearing partition, struts installed.
We determine the installation height of the ridge beam and its length for our home ourselves, making a preliminary sketch on paper.
STEP 5: We manufacture and install rafters.
First of all, we make a template for the rafters. To do this, take a board of the required cross-section that is suitable in length, apply it as shown in Figure 6 and make markings using a small level (blue line):
Figure 6
The height of the block that we placed on the stem to mark the lower cut is equal to the depth of the upper cut. We made it 5 cm.
Using the resulting template, we make all the rafters of the slopes, resting on the ridge beam, and secure them (see Fig. 7):
Figure 7
In such structures, where the rafters are supported not by long floor beams, but by short extensions, we always place small supports under the rafters above the mauerlat, forming a kind of small triangle and relieving the attachment point of the extension to the beam (see Fig. 8):
Figure 8
There is no need to bring these supports further inside the roof, much less place them at the junction of the extension with the beam. Most of the load from the roof is transmitted through them (this can be seen in the calculation program) and the floor beam may simply not withstand it.
Now a little about calculations. When choosing the section of rafters for a given roof, we calculate only one rafter - this is the slope rafter. It is the longest here and its angle of inclination is less than the angle of inclination of the hip rafters (explanation - we call a roof slope in the shape of a trapezoid a slope, a hip - a roof slope in the shape of a triangle). Calculations are made in the “Sling.3” tab. Example results in Figure 9:
Figure 9
Yes, I forgot to say. Who has already downloaded this calculation program from my website before December 1, 2013? There is no “Sling.3” tab. To download the updated version of the program, go to the article again at the link:
This article has also been slightly adjusted thanks to feedback from some readers, for which special thanks to them.
STEP 6: We add an extension and attach wind boards (see Fig. 10). We add enough stems to leave room for attaching the corner stem. For now, we simply sew the wind boards at the corners together, controlling their straightness. Check visually to see if the corners are sagging. If so, place temporary supports under them directly from the ground. After installing the corner extensions, we remove these supports.
Figure 10
STEP 7: We mark and install corner offsets.
First we need to pull the string along the top of the floor beams, as shown in Fig. 11
Figure 11
Now we take a beam of suitable length (the cross-section is the same as for all stems) and place it on top of the corner so that the lace is in the middle of it. From below on this beam we mark the cut lines with a pencil. (see Fig. 12):
Figure 12
We remove the lace and install the timber sawn along the marked lines (see Fig. 13):
Figure 13
We attach the corner extension to the Mauerlat using two roofing corners. We fasten it to the floor beam with a 135° angle and a large nail (250-300 mm). If necessary, bend the 135° corner with a hammer.
This way we install all four corner offsets.
STEP 8: We manufacture and install corner rafters.
The hip roof that I described earlier had the same angles of slope and hips. Here these angles are different and therefore the corner rafter will have its own characteristics. We also make it from two boards of the same section as the rafters. But we sew these boards together not quite usually. One will be slightly lower than the other (about 1 cm, depending on the difference in the angles of the slopes and hips).
So, first of all, we pull 3 laces on each side of the roof. Two along the corner rafters, one along the middle hip rafter (see Fig. 14):
We measure the angle between the lace and the corner stem - the bottom cut. Let's call it “α” (see Fig. 15):
Figure 15
We also mark point “B”
We calculate the angle of the upper cut β = 90°- α
In our example α = 22° and β = 68°.
Now we take a small piece of board with the cross-section of the rafters and saw one end on it at an angle β. We apply the resulting blank to the ridge, combining one edge with the lace, as shown in Fig. 16:
Figure 16
A line was drawn on the workpiece parallel to the side plane of the adjacent rafter of the slope. We will make another cut using it and get a template for the top cut of our corner rafter.
Also, when we apply the workpiece, we need to mark point “A” on the rafters of the slope (see Fig. 17):
Figure 17
Now we make the first half of the corner rafter. To do this, take a board of suitable length. If one board is missing, we sew two boards together. You can sew it temporarily by cutting an inch about a meter long onto self-tapping screws. We make the top cut according to the template. We measure the distance between points “A” and “B”. We transfer it to the rafter and make the bottom cut at an angle “α”.
We install the resulting rafter and secure it (see Fig. 18):
Figure 18
Most likely, due to its length, the first half of the corner rafter will sag. You need to place a temporary stand under it approximately in the middle. It is not shown in my drawings.
Now we make the second half of the corner rafter. To do this, measure the size between points “C” and “D” (see Fig. 19):
Figure 19
We take a board of suitable length, make the top cut at an angle β, measure the distance “S-D”, make the bottom cut at an angle α. We install the second half of the corner rafter and sew it to the first with nails (100 mm). We drive the nails at intervals of approximately 40-50 cm. The result is shown in Fig. 20:
Figure 20
The upper end of the second half of the corner rafter needs to be sawed down again. We do this with a chainsaw right on the spot (Fig. 21):
Figure 21
In the same way, we manufacture and install the three remaining corner rafters.
STEP 9: We install racks under the corner rafters. First of all, it is imperative to install a stand resting on the junction of the corner extension with the floor beam (see Fig. 22):
Figure 22
If the length of the span covered by the corner rafter (its horizontal projection) is more than 7.5 meters, we install more racks at a distance of approximately ¼ of the span from the top point of the corner rafter. If the span is more than 9 meters, add racks in the middle of the corner rafter. In our example, this span is 5.2 meters.
STEP 10: We install two central hip rafters. At the beginning of the 8th step, we already pulled the laces to measure them.
We make the rafters in this way - we measure the angle of the lower gash “γ” with a small tool, calculate the angle of the upper gash “δ”:
δ = 90° - γ
We measure the distance between the points “K-L” and make a rafter along it. We file the ends at the angles we have determined. After this, the upper end needs to be filed down (sharpened) again, taking into account the angle “φ”, which we also measure using a small tool (see Fig. 23):
Figure 23
STEP 11: Add offset to the corners. We make the outermost extensions, which do not reach the mauerlat, lightweight, from a 50x200 mm board (see Fig. 24):
Figure 24
STEP 12: We install spigots. I described in detail how to make spigots in the first article about. Here the principle is absolutely the same, so I will not repeat it (see Fig. 25):
Figure 25
We attach the brackets to the corner rafters using metal corner 135°, bending it if necessary.
After installing all the frames, all we have to do is hem the cornices from below and make the sheathing. We have already talked about this many times.
